Acid-soluble proteins and spore coat proteins are being isolated and characterized from spores of Bacillus subtilis. Antisera against purified polypeptides are being used to assay for messenger activity in total RNA from sporulating cells so that times of in vivo transcription and expression of the structural genes for these sporulation-specific components can be compared. The antisera will also be used to enrich for messenger fractions which can be used as probes for cloning of the structural genes.